The element on the left side of the &= operator can be a simple scalar variable, a property, or an element of an array. The variable or property cannot be ReadOnly (Visual Basic). The &= operator concatenates the String expression on its right to the String variable or property on its left, and assigns the result to the variable or property on its left.

Overloading

The & Operator (Visual Basic) can be overloaded, which means that a class or structure can redefine its behavior when an operand has the type of that class or structure. Overloading the & operator affects the behavior of the &= operator. If your code uses &= on a class or structure that overloads &, be sure you understand its redefined behavior. For more information, see Operator Procedures (Visual Basic).